Efficient use of the resources of a wireless local-area network (WLAN) is important to provide bandwidth and acceptable response times to the users of the WLAN. Moreover, wireless devices may need to operate with both newer protocols and with legacy device protocols.
Additionally, there may be errors in receiving data, and different ways of transmitting the data over the wireless medium may reduce the number of errors or may provide the receiver with additional information that may enable the receiver to correct errors.